Brazilian airline Gol expects an operating loss this year after posting a hefty quarterly net loss due to fuel costs and a currency swing.

Gol booked a second-quarter net loss of BRR805 million reais (USD$ 397 million), more than double its loss of BRR358 million a year earlier.

A 26 percent increase in fuel costs and 42 percent rise in aircraft rental costs contributed to the plunging bottom line. A volatile exchange rate added BRR333 million reais to the loss.

Brazil’s currency, the real, slid 10 percent against the US dollar in the quarter, driving up the cost of foreign debt.

Earnings before interest and taxes (EBIT), fell to negative BRR355 million reais in the quarter. In the earnings release, Gol issued a new forecast for negative EBIT this year, scrapping a prior forecast for EBIT equal to between 4 percent and 7 percent of revenue.

Gol also cut its outlook for flight offerings this year by nearly 5 percent. The airline now expects to offer between 48 billion and 49 billion available seat-km in 2012, helping to reduce its fuel consumption by 6 percent compared with its prior outlook.